High power lasers are used for laser cutting, welding, and folding of metals and polymers. High peak power and nanosecond pulses enable effective marking and engraving. The additional power and better beam quality provide cleaner cut edges and faster cutting speeds. A high power laser system may comprise an oscillator, multiple stages of fiber pre-amplifiers, and free space solid state power amplifiers. The oscillator sets the laser's wavelength, pulse width, and repetition rate, while the fiber amplifiers boost the laser power to a required level. The last module of the high power laser includes a free space solid state power amplifier for power amplifying the laser beam received from the fiber pre-amplifier.
In the current high power laser system, the laser light exiting from the fiber pre-amplifier propagates in free space entering the free space solid state power amplifier. The alignment between the fiber pre-amplifier and the free space solid state power amplifier is critical. An offset angle on the order of 0.1 degree may sufficiently degrade the power of the output laser light. Accordingly, high power laser systems requiring less critical alignment are desired.
The positions of the fiber pre-amplifier and the free space solid state power amplifier are fixed to keep the required alignment. The available space is often not suitable or not enough for the position setting of the fiber pre-amplifier and the free space solid state power amplifier. Accordingly, high power laser systems having fiber pre-amplifier and free space solid state power amplifiers that can be setup with flexibility are also desired.
Corresponding reference characters indicate corresponding components throughout the several views of the drawings. Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of various embodiments of the present invention.